Drop bottom container

ABSTRACT

A drop bottom container adapted for use with a fork lift. The container has a pair of hinged door members for closing its open bottom which are latched into closed position and swing by gravity to the open position when the latch is released. The door members are yieldingly limited at the open position to prevent uncontrolled swinging movement. The latching mechanism is released manually, initially with minimum movement and maximum mechanical advantage to overcome load forces, followed by progressively increased movement to quickly effect the release even with the container in a fully loaded condition. Means are also included for closing the doors as the container is lowered, which includes a vertically disposed longitudinal member projecting below the open doors which engages the ground with such lowering movement.

iJnited States Patent [191 Fagre et al.

[ Mar. 19, 1974 1 DROP BOTTOM CONTAINER [75] Inventors: Raymond C. Fagre, 4125 W. 45th St., Edina, Minn. 55424; Elvin E. Kaiser, Minneapolis, Minn.

[73] Assignee: said Fagre, by said Kaiser [22] Filed: Sept. 1, 1972 [21] Appl. No.: 285,806

[52] US. Cl 294/71,'214/307, 294/69 R [51] Int. Cl. B66c 3/00 [58] Field of Search 294/69 R, 71, 72; 214/300,

[56] References Cited UNITED STATES PATENTS 2,801,126 7/1957 White et al..; 294/71 3.608,757 9/1971 Tary 294/71 X Primary Examiner-Even C. Blunk Assistant Examiner-Johnny D. Cherry V Attorney, Agent, or FirmMerchant, Gould, Smith & Edell 1 1 ABSTRACT A drop bottom container adapted for use with a fork lift. The container has a pair of hinged door members for closing its open bottom which are latched into closed position and swing by gravity to the open position when the latch is released. The door members are yieldingly limited at theopen position to prevent uncontrolled swinging movement. The latching mechanism is released manually, initially with minimum movement and maximum mechanical advantage to overcome load forces, followed by progressively increased movement to quickly effect the release even with the container in a fully loaded condition. Means are also included for closing the doors as the container is lowered, which includes a vertically disposed longitudinal member projecting below the open doors which engages the ground with such lowering movement.

PATENTEDFMR w 1914 3397' 878 SHEET 1 BF 2 PATENTEDMAR 1 9 m4 3.1797378 SHEET 2 [1F 2 DROP BOTTOM CONTAINER The invention relates generally to drop bottom containers, and is specifically directed to a drop bottom container usuable with a fork lift and fully controllable by the fork lift operator without leaving the vehicle.

Drop bottom containers are extremely useful in material conveying applications which are adapted for the elevated discharge of material. One specific example in which drop bottom containers are particularly useful is in industrial areas which requires continuous clean-up. The container is placed in a convenient, accessible location where waste material, refuse and the like can be dumped into the container over a period of time until it is filled. The contents are then transferred by elevating the container over a suitable receptacle and allowing the bottom closure members to swing open and thereby discharge the container contents.

For areas that normally employ fork lifts in their operations, the drop bottom container is easily adapted for cooperation with the lifting bifurcated members of the vehicle. One difficulty that arises with such use, however, is the need for the fork lift operator to get down from his vehicle to actuate the container latching mechanism at the time the contents are to be discharged; or, alternatively, for a second person to be present when the fork lift reaches the discharge area. The problem is compounded by the fact that discharge of the contents occurs only when the container is elevated. thus making it difficult as well as dangerous to reach and actuate the latching mechanism. Further, when the container is heavily loaded with material, the latching mechanism is subjected to extreme binding forces thus making it difficult to be actuated to the release position.

This problem extends to closing of the container, which is usually away from the discharge area. Closing the container requires either that the operator again leave his vehicle, or the availability of a second person to close the container while the operator remains on the vehicle.

Our invention is the result of an endeavor to provide a drop bottom container usuable with a fork lift and which can be simply and easily opened and closed by the fork lift operator without leaving the vehicle. This is accomplished with a unique linkage and latching mechanism which guidably controls downward swinging movement of the hinged closure members. The latching mechanism is constructed so that its initial releasing movement is minimal, but with maximum mechanical advantage to overcome binding or shear forces exerted thereon by the container load acting through the bottom closure members. Movement of the latching mechanism then increases progressively until the closure members are released to discharge the container contents.

To close the doors, an elongated guide member is provided which slides vertically relative to the container. The closure members are pivotally connected to the longitudinal guide member by linkage arms in such a manner that the longitudinal member always projects below the closure members in the open position. Consequently, lowering of the container causes the longitudinal guide members to engage the supporting surface, thus carrying the closure members upwardly toward the closed position at which point the latching mechanism retains them in place.

A further problem with existing devices stems from uncontrolled swinging movement of the closure members at the time they are released. Our invention further contemplates resilient means which limit movement of the closure members in a yielding manner to prevent such uncontrolled swinging. The resilient means are adjustable to compensate for changes in their resiliency due to repeated use and resulting wear.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an end elevational view of a drop bottom container embodying the inventive principle, the closure members of said container being shown in a closed position.

FIG. 2 is the end elevational view of FIG. I with the closure members released to an open or discharge position;

. FIG. 3 is a side elevational view of the drop bottom container with the closure members in their closed position;

FIG. 4 is an enlarged fragmentary sectional view of the container taken along the line 44 of FIG. 1;

FIG. 5 is an enlarged fragmentary sectional view taken along the line 5-5 of FIG. 4!, showing with particularity the latching mechanism and the means for resiliently limiting swinging movement of the closure members;

FIG. 6 is an end elevational view of an alternative embodiment of the inventive drop bottom container;

FIG. 7 is a fragmentary side elevational view of a drop bottom container of FIG. 6; and

FIG. 8 is an enlarged fragmentary sectional view taken along the line 8-8 of FIG. 7, showing with particularity alternative structure for resiliently limiting swinging movement of the closure members.

DESCRIPTION OF THE PREFERRED EMBODIMENTS With initial reference to FIGS. 1-3, a drop bottom container embodying the inventive principle is represented generally by the numeral 11. Container I1 is generally rectangular in'shape, being formed from two rectangular side plates 12 and end plates 13 welded together at their corners and reinforced by appropriate lengths 14 of angle iron.

The top edge of each end plate 13 is notched at each outer corner to receive elongated tubular members 15 which are rigidly affixed by welding. The elongated members 15 are sized and spaced to define receiving slots 16 for the bifurcated lifting members of a fork lift. Tubular members 17 which are square in cross section are affixed at each end of the container 11 between elongated members 15 for purposes of support, as are similar end members 18 and side members 19 along the bottom edge of the container 11; A square tubular member 21 is vertically affixed on each end plate 13 between the tubular members 17 and 19 for a purpose described in greater detail below.

Lifting frames represented generally by the numeral 22 are formed from the same square tubular stock, one frame 22 being affixed to the top surface of each elongated member 15. As shown in FIG. 3, each of the lifting frames 22 defines two longitudinal lifting slots 23 sized and spaced to receive bifurcated lifting members 24 (FIGS. 1 and 2) of a fork lift.

As described, container 11 is a four sided structure open both at its top and bottom. The bottom is closeable by a pair of closure members or doors 25 each of which runs the length of container 11 and is pivotally connected to the associated side tubular member 19 by hinges 26. Each of the closure members 25 comprises a rectangular frame 27 formed from square tubular stock and a bottom plate 28 affixed thereto. This particular sturcture enables the container 11 to hold a quantity of liquid in pan fashion, thereby eliminating dripping that might otherwise occur. As best shown in FIG. 1, the width of the closure members 25 enables them to together effectively close the open bottom of container 11 when moved upwardly to the closed position.

With additional reference to FIG. 4, a tubular member 29, also square in cross section, is slidably disposed in each of the vertical tubular members 21. Each of the closure members 25 is operably connected at each end to the slidable members 29 by a linkage arm 31. The upper ends of the four linkage arms 31 are pivotally connected to the slidable member 29 by a pin 32 which is guidably movable in a slot 33 formed in the vertical tubular member 21. Thus, it will be appreciated that upand down movement of the sliding member 29 within the tubular member 21 effects a corresponding opening and closing movement of the closure members 25. It is also to be observed, as particularly shown in FIG. 2, that the slidable member 29 projects below the lower most point of closure members 25 in any position but the closed position, at which point these members move into the bottom plane of container 11.

To prevent uncontrolled downward swinging movement of the closure members 25, means are included for yieldingly or resiliently resisting movement beyond a predetermined limit point. With additional reference to FIG. 5, a small square plate 35 is affixed inside the vertical member 21 near its top. A resilient rubber block 36 is disposed on the plate 35 and carries a downwardly projecting, threaded eye-bolt 37. A U-shaped member 38 hangs from the eye of the bolt 37, and a length of flat'bar stock 39, formed into an elongated loop, is welded to the respective legs of the U-shaped member 38. The flat bar stock loop 39 encircles the pivot pin 32, and. with the aid of the rubber block 36,

acts as a resilient stop for the closure members 25 as they reach their open position by reason of engagement with the pin 32. The limiting position of the clsure members 25 is adjustable by reason of the threaded nut for eye-bolt 37.

A latching and linkage mechanism represented generally by the numeral 41 serves to hold the closure members 25 in a closed position and to release these members to discharge contents in container 11. The mechanism 41 includes operable portions on each end of the container 11 which are interconnected by an elongated shaft 42 rotatably mounted in a pair of bearing members 43. On that end of container 11 shown in FIG. 1, a first linkage arm 44 is rigidly affixed to shaft 42 at an obtuse angle. On the opposite end, a linkage arm 44' is affixed to shaft 42 in the same manner, the linkage arm 44'. differing from the linkage arm 44 in length for a purpose described in further detail below.

Respectively connected in pivotal fashion to each of the linkage arms 44 and 44' is a second linkage arm 45, which is in turn pivotally connected to one end of a third linkage arm 46. The opposite end of linkage arm 46 is connected to a stationary pivot point 47 carried at the end of a short projecting member 48. Intermediate the ends of third linkage arm 46, a latch pin 49 is pivotally connected. As best shown in FIG. 5, a small rectangular plate 51 is welded to the side of each vertical member 21, and the latch pin 49 cooperates with alignable bores formed in the plate 51, the vertical member 21 and the slidable member 29. The length of latch pin 49 is such that, in the release position, it still remains in the bore of plate 51. A coil spring 52 is connected between a stationary hook 53 on end plate 13 and an intermediate point on second linkage arm to normally bias latching pin 49 into the respective bores.

With reference to FIG. 2, a pulley 54 is mounted on he container 11 at an upper corner, and a chain 55 passes over the.v pulley .54 and is connected to the projecting end oflinkage arm 44. Chain 55 is of sufficient length to extend to the operating area of the fork lift, thus enabling the operator to pull the chain and actuate mechanism 41 to release the closure members 25. A pair of hooks 57 mounted on one of the corner members l4 permit the chain to be wound up when not in use.

As shown in FIG. 1, the pivotal connection between linkage arms 44 and 45 occupies a slightly over-center position to assist in maintaining the latch pin 49 in its latch position. When the bore of slidable member 29 aligns itself with the bores of vertical member 21 and plate 51, which occurs when the closure members 25 are in the closed position, latch pin 49 projects into the aligned bores and serves to hold the closure members 25 in this position. Pulling of the chain 55 draws the linkage arms 45 and 46 away from the vertical member 21 until such point that the latch pin 49 is removed from the bore of slidable member 29 to effect its release as well as the release of closure members 25. It is to be observed that the pivotal connections between linkage arms 44' and 45 (and linkage arms 44 and 45) move radially, and the initial movement thereof from the latch position is predominantly lateral relative to the line of movement of the latch pin 49. Therefore, this movement has an increasingly greater effect on the retraction of pin. 49 from the aligned bores. In other words, there is little initial movement on the part of latch pin 49 for a corresponding larger movement of linkage arm 44". Although this initial retractive movement of the latch pin 49 is slight, it is with great mechanical advantage, thus enabling the pin to be retracted with a moderate pull on the chain 55 although the contents of container 11 exert a significant binding or shearing force on the latch pin 49 through the closure members 25, linkage arms 31, pivot pin 32 and slidable member 29. V

Further movement of the linkage arm 44' effects greater and greater movement of its pivot point with linkage arm 45 away from the center line of vertical member 2l,thus accelerating the retractive movement of latch pin 49 once its initial movement has begun. A pair of stops 58 (FIG. 2) limit movement of linkage arm 44 in both directions.

Also as shown in FIGS. 1 and 2, a flag member 56 is rigidly affixed to the shaft 42 in such a manner that it projects outwardly to indicate when the closure members 25 are in the release position. Flag member 56 Thus. the end and side tubular members 18a and 19a l0 extend peripherally around the upperedge of the container 110, whereas the tubular members 17a are disposed along the bottom edge. Rectangular tubular members a are also affixed along the bottom edge of the container 11a to provide lower lifting slots for'the l5 bifurcated lifting members of a fork lift. Triangular plates 20a are commonly affixed to the top surface tubular members 15a and each corner member 14a to offer reinforcing support during the lifting operation.

The hinges 26a are mounted on the lower face of the tubular members 15a, and the closure members a themselves are modified by reversing the position of the rectangular frame 27a and bottom plate 28a.

The position of the several components of latching and lifting mechanism 41a are also reversed. with the latch pin 49a disposed at a somewhat higher intermediate point with respect to the vertical tubular member 21a. Container 11a also includes modified structure for providing the resilient limiting function for the closure members 25a, as shown specifically in FIG. 8. This modified structure includes a short square tubular member 6111 slightly smaller in cross sectional size than the tubular member 29a to permit sliding movement therein. A coil spring 62a is interconnected between the eye-bolt 37a and a second eye-bolt 63a affixed to the short tubular member 61a. A stop 64a for the short tubular member 61a is welded to the extreme top end of slidable member 29a for engagement with the member 61a as the tubular member 29a slides downwardly. Thus, with release of the closure members 25a, tubular member 29a is carried downwardly therewith until the stop member 64a engages the short tubular member 61a. At this point, further downward movement on the part of closure members 25a is resiliently limited by the spring 620. The position of eye-bolt 37a is adjustable by the nut associated therewith to effect the proper opening position of closure members 25a, and also to compensate for changes in the spring 62a occurring from repeated use. I

Operation of the containers 11 and 11a is essentially the same, and will be described only with respect to container 11 as set forth in FIGS. 1-5. With the container ll resting on a supporting surface with the closure members 25 in their closed position as shown in FIG. 1, material may be dumped therein until filled or at such time it is desired to discharge the material. Ifa fork lift is used to transport the container 11, its bifurcated lifting members 24 are either inserted transversely through the slots 23 defined by lifting frame 22, or longitudinally through the slots 16 defined by tubular members 15. The length of chain 55 is placed in an accessible position to the fork lift operator, and the container 11 is then lifted by the fork lift and transported to a desirable discharge area. The container movement initially begins with maximum mechanical advantage and relatively little movement, followed by progressively increased movement on the part of latch pin 49 until release of the tublar member 29 is effected. At this point, closure members 25 are released and swing downwardly until pivot pin 32 engages the .bar stock loop 39. Further downward movement of the closure members 25 is resiliently limited by the rubber block 36, thus preventing uncontrolled and undesired swinging movements by the closure members 25. Flag member 56 moves to the position shown in FIG. 2 indicating that container 11 is in a discharge state.

After the contents of container 11 .have been fully discharged, the container 11 is lowered toward the supporting surface. The slidable tubular member 29 initially engages the ground with such lowering movement, thus causing the closure members 25 to swing upwardly to their closed position. As the container reaches the supporting surface, the bore in tubular member 29 becomes aligned with the bores in plate 51 and the bias of coil spring 52 causes latch pin 49 to be projected into the latching position. Container 11 is'at this point ready to be refilled, and the fork lift can then be removed and used for other purposes.

We claim:

1. In a drop bottom container having at least one closure member pivotally connected thereto for movement between open and closed positions and disposed to support at least a portion of the container load in the closed position, the improvement comprising:

a. latching means movable between latch and release positions for releasably holding the closure member in said closed position, the latching means being subjected to container loadforces when in said latch position;

b. and control means for moving the latching means from the latch position to the release position at a progressive rate'of speed and with decreasing mechanical advantage.

2. The structure defined by claim ll, wherein the latching means has a predetermined line of movement between said latch and release positions, and the control means comprises:

a. a linkage member having one end pivotally mounted to the container, the free end being so disposed relative to the latching means when in the latched position that rotational movement of said free end is initially predominantly lateral with respect to the line of latching means movement;

b. and means operatively connecting the linkage member to the latching means.

3. The structure defined by claim 2, wherein the connecting means comprises: I

a. a second linkage member having one end pivotally mounted on the container, the latching means being operably connected to the second linkage member at a point spaced from its pivotal mounting;

b. and a third linkage member pivotally connecting the first named linkage member to the second linkage member.

4. The structure defined by claim 3, wherein the'pivotal connection between the first and third linkage member is disposed in an over center position with the latching means in said latch position. I

5. The structure defined by claim 1, and further comprising means for biasing the latching means toward the latch position.

6. The structure defined by claim 1, wherein:

a. the closure member is pivotally connected to an elongated member vertically movable relative to a guide member carried by the container, the elongated and guide members each having an aperture forming therein, the apertures being alignable when the closure member is in its closed position;

b. and the latching means comprises a latch pin retractably insertable into said aligned apertures.

7. The structure defined by claim 1, and further comprising means for manually operating the control means.

8. The structure defined by claim 1 which further comprises:

a. an elongated member carried by the container and guidably movable relative thereto:

b. and linkage means operably connecting the elongated member with the closure member;

c. said elongated member projecting below the closure member in its open position for engagement by a supporting surface as the container is lowered toward said surface to move the closure member to its closed position with said lowering movement.

9. A drop bottom container comprising:

a. a liftable container having an open bottom and adapted to receive material and to .discharge mate rial in a position elevated from a supporting surface;

b. a closure member hingeably connected to the container to open and close said open bottom;

c. an elongated member carried by the container and guidably movable relative thereto;

d. linkage means operably connecting the elongated member with the closure member;

e. and resilient limiting means cooperably disposed between the elongated member and the container to resiliently and yieldingly restrain downward movement of the closure member upon reaching a predetermined open position.

10. The structure defined by claim"9, wherein the container further comprises a vertically disposed, tubular guide member, the elongated member being slidably disposed in the guide member.

11. The drop bottom container defined by claim 10, wherein a. an aperture is formed in each of the elongated and guide members, the apertures being disposed for alignment when the closure member is in its closed position;

b. and the releasably latching means comprises a latch pin insertable into the aligned apertures.

12. The drop bottom container defined by claim 19, wherein the guide member has an elongated slot formed therein, and the linkage means comprises a linkage member pivotally connected to the closure member and to the elongated member through said elongated slot.

13. The structure defined by claim 10, wherein the elongated member is tubular, and the limiting means comprises:

a. a first stop member slidably disposed within the elongated member;

b. a second stop member affixed to the elongated member proximate its top and abuttably engageable with the first stop member;

c. and spring means connected to the container above the second stop member and to the first stop member.

14. The structure defined by claim 13, wherein the spring means comprises a coil spring the upper end of which is adjustably connected to a support plate disposed within and affixed to the tubular guide member.

15. The structure defined by claim 10, wherein the elongated member is tubular, and the limiting means comprises:

a. a transverse stop member disposed within and affixed to the elongated member;

b. an elongated loop of material disposed within the elongated member and encircling the transverse stop member;

c. and means for resiliently connecting the elongated loop to the container at a point above the elongated member.

16. The structure defined by claim 15, wherein the resilient connecting means comprises:

a. a support plate disposed within and affixed to the tubular guide member proximate its top;

b. a thickness of resilient material carried on top of the support plate;

c. a threaded bolt having one end supportably corinected to the elongated loop, the other end projecting through the support plate and thickness of resilient material;

d. and a nut adjustably disposed on the threaded bolt above the resilient material.

17. The structure defined by claim 15, wherein:

a. the guide member has an elongated slot formed therein;

b. and the connecting means comprises a linkage member pivotally connected to the closure member and to the elongated member through said elongated slot;

c. the pivotal connection between the linkage and elongated members comprising said transverse stop member.

18. The drop bottom container defined by claim Q, wherein the container further comprises support means defining at least two horizontally disposed, parallel slots sized and spaced to receive the bifurcated members of a fork lift.

19. The drop bottom container defined by claim 18, wherein the container is rectangular in shape, and the support means defines two such pairs of slots relatively perpendicularly disposed to permit lifting of the container by a fork lift from any side thereof.

20. The drop bottom container defined by claim 9, wherein the closure member is constructed in pan fashion to hold a predetermined quantity of liquid.

21. The structure defined by claim 9, wherein the elongated member projects below the closure member in its open position for engagement by the supporting surface as the container is lowered toward said surface to move the closure member to its closed position with said lowering movement. 

1. In a drop bottom container having at least one closure member pivotally connected thereto for movement between open and closed positions and disposed to support at least a portion of the container load in the closed position, the improvement comprising: a. latching means movable between latch aNd release positions for releasably holding the closure member in said closed position, the latching means being subjected to container load forces when in said latch position; b. and control means for moving the latching means from the latch position to the release position at a progressive rate of speed and with decreasing mechanical advantage.
 2. The structure defined by claim 1, wherein the latching means has a predetermined line of movement between said latch and release positions, and the control means comprises: a. a linkage member having one end pivotally mounted to the container, the free end being so disposed relative to the latching means when in the latched position that rotational movement of said free end is initially predominantly lateral with respect to the line of latching means movement; b. and means operatively connecting the linkage member to the latching means.
 3. The structure defined by claim 2, wherein the connecting means comprises: a. a second linkage member having one end pivotally mounted on the container, the latching means being operably connected to the second linkage member at a point spaced from its pivotal mounting; b. and a third linkage member pivotally connecting the first named linkage member to the second linkage member.
 4. The structure defined by claim 3, wherein the pivotal connection between the first and third linkage member is disposed in an over center position with the latching means in said latch position.
 5. The structure defined by claim 1, and further comprising means for biasing the latching means toward the latch position.
 6. The structure defined by claim 1, wherein: a. the closure member is pivotally connected to an elongated member vertically movable relative to a guide member carried by the container, the elongated and guide members each having an aperture forming therein, the apertures being alignable when the closure member is in its closed position; b. and the latching means comprises a latch pin retractably insertable into said aligned apertures.
 7. The structure defined by claim 1, and further comprising means for manually operating the control means.
 8. The structure defined by claim 1 which further comprises: a. an elongated member carried by the container and guidably movable relative thereto: b. and linkage means operably connecting the elongated member with the closure member; c. said elongated member projecting below the closure member in its open position for engagement by a supporting surface as the container is lowered toward said surface to move the closure member to its closed position with said lowering movement.
 9. A drop bottom container comprising: a. a liftable container having an open bottom and adapted to receive material and to discharge material in a position elevated from a supporting surface; b. a closure member hingeably connected to the container to open and close said open bottom; c. an elongated member carried by the container and guidably movable relative thereto; d. linkage means operably connecting the elongated member with the closure member; e. and resilient limiting means cooperably disposed between the elongated member and the container to resiliently and yieldingly restrain downward movement of the closure member upon reaching a predetermined open position.
 10. The structure defined by claim 9, wherein the container further comprises a vertically disposed, tubular guide member, the elongated member being slidably disposed in the guide member.
 11. The drop bottom container defined by claim 10, wherein a. an aperture is formed in each of the elongated and guide members, the apertures being disposed for alignment when the closure member is in its closed position; b. and the releasably latching means comprises a latch pin insertable into the aligned apertures.
 12. The drop bottom container defined by claim 19, wherein the guide member has an elongated slot formed thereIn, and the linkage means comprises a linkage member pivotally connected to the closure member and to the elongated member through said elongated slot.
 13. The structure defined by claim 10, wherein the elongated member is tubular, and the limiting means comprises: a. a first stop member slidably disposed within the elongated member; b. a second stop member affixed to the elongated member proximate its top and abuttably engageable with the first stop member; c. and spring means connected to the container above the second stop member and to the first stop member.
 14. The structure defined by claim 13, wherein the spring means comprises a coil spring the upper end of which is adjustably connected to a support plate disposed within and affixed to the tubular guide member.
 15. The structure defined by claim 10, wherein the elongated member is tubular, and the limiting means comprises: a. a transverse stop member disposed within and affixed to the elongated member; b. an elongated loop of material disposed within the elongated member and encircling the transverse stop member; c. and means for resiliently connecting the elongated loop to the container at a point above the elongated member.
 16. The structure defined by claim 15, wherein the resilient connecting means comprises: a. a support plate disposed within and affixed to the tubular guide member proximate its top; b. a thickness of resilient material carried on top of the support plate; c. a threaded bolt having one end supportably connected to the elongated loop, the other end projecting through the support plate and thickness of resilient material; d. and a nut adjustably disposed on the threaded bolt above the resilient material.
 17. The structure defined by claim 15, wherein: a. the guide member has an elongated slot formed therein; b. and the connecting means comprises a linkage member pivotally connected to the closure member and to the elongated member through said elongated slot; c. the pivotal connection between the linkage and elongated members comprising said transverse stop member.
 18. The drop bottom container defined by claim 9, wherein the container further comprises support means defining at least two horizontally disposed, parallel slots sized and spaced to receive the bifurcated members of a fork lift.
 19. The drop bottom container defined by claim 18, wherein the container is rectangular in shape, and the support means defines two such pairs of slots relatively perpendicularly disposed to permit lifting of the container by a fork lift from any side thereof.
 20. The drop bottom container defined by claim 9, wherein the closure member is constructed in pan fashion to hold a predetermined quantity of liquid.
 21. The structure defined by claim 9, wherein the elongated member projects below the closure member in its open position for engagement by the supporting surface as the container is lowered toward said surface to move the closure member to its closed position with said lowering movement. 